In order to solve the problem that it was difficult for permanent magnet synchronous motor to reconstruct the current in the low modulation area and the boundary area of the sector when the singleresistance current was sampled, a novel singleresistance current reconstruction technique was proposed. Firstly, the principle of threephase current reconstruction technique was studied, the region in which the current was unable to reconstruct was defined as nonobservation area, and the blind region of current reconstruction in the nonobservation area was analyzed. Secondly, using the pulse width modulation (PWM) shift method to reconstruct the current in the nonobservation area, it was found that there were still some nonobservation areas where only the singlephase current could be measured and the current could not be reconstructed. Aiming at this problem, the current observer without the motor and load parameters was designed to estimate the threephase current, which was easy to implement. Finally, the experimental results showed that the proposed novel singleresistor current reconstruction technique was feasible and valuable.